Showing papers on "Soil stabilization published in 1991"

Combining Industrial Wastes with Lime for Soil Stabilization

Abstract: Using a geotechnical viewpoint, this paper proposes a potential, partial solution to solve some of the problems posed by increasing amounts of certain types of sludgy industrial waste. The primary objective of this study is to examine the potential for burning various industrial wastes combined with lime, in certain proportions, to produce a by-product having cementing characteristics similar to ordinary portland cement (OPC). It is found that the percentages of main cementitious compounds in this new cement-like stabilizer are comparable to those of OPC. The by-product also shows promise for use in stabilizing a loam soil. The contribution of ettringite to strength development is discussed. It is found that this new type of additive can be used to stabilize loam soil for subgrade purposes.

Soil Stabilization and Grouting

Abstract: Soil stabilization and grouting are methods of soil improvement. Soil improvement is a combination of physical and chemical methods for regional or mass densification, reinforcement, cementation, and control of drainage and volume stability of soil when it is used as a construction material.

Stabilization of Soil with Lime Columns

Abstract: The behavior of very soft clay or silt can be improved with lime or cement columns. In this soil stabilization method, the soft soil is mixed in situ either with unslaked lime (CaO) or with cement using a tool shaped like a giant dough mixer, as illustrated in Figure 24.1. Other materials can be used, such as gypsum (Holm et al., 1983a), fly-ash and furnace slag (Nieminen, 1978), hydroxyaluminum (Bryhn et al., 1983), and potassium chloride (Eggestad and Sem, 1976).

Epoxy-resin-based chemical stabilization of a fine, poorly graded soil system

Abstract: Results are described of a research effort on the epoxy-based treatment of fine, poorly graded soil found at some localized low-duty airport sites and in the north slopes of Alaska. Statistical models are developed for the stabilization of clay-silt pavement systems at low-duty airports. A nontraditional method of soil stabilization that improves the subgrade strength properties of poorly graded clay-silt was identified. This soil system is considered one of the most difficult soil types to stabilize, in part because of its poor particle size distribution. Among several organic additives tested, the two-part epoxy system--bisphenol A/epichlorohydrin resin plus a polyamide hardener--gave the best result as measured by the dry California bearing ratio (CBR) test. The choice of the dry CBR test performed to ASTM specification was motivated by a need to capture optimum moisture content as an experimental variable. Within the limits of the laboratory test conditions, the statistical regression models developed support the hypothesis that the marginal increase in CBR values caused by a 1% increase in epoxy resin application is 11.1 and the marginal degradation of CBR caused by a 1% increase in moisture level in -5.6. Also, only additive level, moisture content, and temperature are significant variables influencing soil strength.

Engineering properties of incinerator residue

Abstract: For highly urbanized cities where there is a scarcity of available land for landfilling, incineration may be a better method of solid‐waste disposal. After incineration about 20% by weight of ash and other residues are produced. Both the washed clinker and fly ash collected from the refuse‐incineration plant have the prerequisite properties for use in geotechnical applications. The washed clinker is essentially a granular material of irregular shape. Fly ash is predominantly silt‐sized, spherical particles. The specific gravities of the washed clinker and fly ash are 2.67 and 2.45 respectively. Both materials exhibit high strength and are relatively free‐draining, typical of granular materials. The fly ash could be used as an admixture in the stabilization of soft soil. The clay samples treated with fly ash show substantially improved shear strengths and lower compressive properties.

Technique for Using Fine-Grained Soil in Reinforced Earth

Abstract: The performance of reinforced earth structures depends on the mobilization of interfacial shearing resistance between soil and reinforcement. This criterion typically eliminates the use of fine-grained soil as a backfill material in reinforced earth structures. Considering the distribution of induced interfacial shear stress in soil around the surface of the reinforcement, it has been shown that only a thin zone of frictional material around the reinforcement is required to mobilize almost full interfacial shearing resistance of sand. Six series of pullout tests have been conducted, with different types of reinforcement, to study the effect of thickness of sand (frictional material) around the reinforcement on the pullout resistance. Sawdust and kaolin clay have been used as bulk backfill material, providing the soil with negligible friction. With low-friction-strength soil as bulk material, a 15-mm thickness of sand around the reinforcement is required to increase the interfacial shearing resistance to that with sand as the bulk material. With this new technique, low-frictional fine-grained soils can be used as bulk backfill material in reinforced earth constructions.

Fly ash in concrete : properties and performance : report of technical committee 67-FAB, use of fly ash in building, RILEM (The International Union of Testing and Research laboratories for Materials and Structures

Abstract: Preface. Introduction. Characterization of fly ash. Origin of coal and burning conditions. Properties of fly ash. Fresh mortar and concrete with fly ash. Properties of freshly mixed mortar and concrete. Admixtures and air content. Setting. Plastic shrinkage. Hardened mortar and concrete with fly ash. Hydration and strength. Deformations. Frost resistance. Chemical resistance. Carbonation. Chloride attack on steel reinforcement. Electrical resistivity. Other uses of fly ash. Cement. Binders with fly ash. Precast concrete. Bricks and blocks. Lightweight aggregates. Fly ash in road construction. Fly ash in soil stabilization. Fly as asphalt-filler. Fly ash as fill. Waste neutralizaton and stabilization. References. Appendix. RILEM Recommendations: Fly ash in concrete - Test methods. Index.

Soil-Cement Mixed Wall Technique

Abstract: This paper introduces the soil-cement mixed wall technique and its applications for the installation of cutoff walls, excavation support walls and soil-crete columns for soil stabilization. The factors that affect the quality of the soil-cement mixed wall are discussed. The engineering properties and design basis of various applications are presented together with the first two soil-cement mixed wall projects in the United States.

Performance of precast driven piles in marine clay

Abstract: A field study is described which investigated the load transfer behavior of precast reinforced concrete piles driven through marine clay and founded in residual soil and weathered rock of sedimenatry origin. It was found that the pile capacity was time dependent for a long period after intital pile installation due to the progress of soil setup in the marine clay. To have an accurate capacity estimation, stress-wave measurements should be made by restriking the pile about one month after installation with a sufficiently large hammer to activate full shaft and toe resistances. Static approaches were found not to be suitable. Pore pressure measurements provided useful insight on the dissipation of excess pore pressure generated by pile driving. These and other study findings are discsussed.

Liquid calcium chloride for dust control and base stabilization of unpaved road systems

Abstract: The use of liquid calcium chloride on unpaved roads as a dust control agent and as a base stabilization material is examined. In the first section, a description is provided of how calcium chloride controls dust and the benefits it produces. The performance of calcium chloride is compared with that of other commonly used dust control agents. Recommended guidelines and application rates for controlling dust on unpaved roads with calcium chloride are then given. The second section provides a description of how calcium chloride stabilizes unpaved road bases and lists the seven ways the chemical helps build stronger roads. Recommended guidelines and application rates for stabilizing road bases with calcium chloride are provided.

Full-depth reclamation with calcium chloride

Abstract: Low-volume secondary roads requiring rehabilitation can be restored using the full-depth reclamation process with calcium chloride to achieve increased bearing capacity, minimize frost heave damage, and reduce highway maintenance expense Full-depth reclamation uses a pulverizer to grind the asphalt surface, blending it with the gravel base to a depth of 8 in The road is then reshaped and approximately three-quarters of the required calcium chloride is added Additional pulverization is performed to ensure a uniform mixture of road material and calcium chloride Following this, the road is graded, rolled, and final application of calcium chloride is made Testing of full-depth reclamation with and without calcium chloride addition indicates that use of the reclamation process achieves a dense, stable, granular layer, improving overall pavement strength compared to original pavement condition The addition of calcium chloride enhances this stabilization of the granular layer 10% beyond strength measured in the untreated reclaimed road section A 50 to 60% reduction in frost heave can be expected in reclaimed sections of road using calcium chloride

Stabilization of alluvial soils with cement and cement-rice husk ash blend for low-volume road construction in bangladesh

Abstract: Rice husk, produced by milling rice, has been used to a large extent as boiler fuel in rice mills in Bangladesh. The rice husk ash (RHA) produced has created a disposal problem. A study was conducted to examine the characteristics of alluvial silty soils stabilized with ordinary portland cement and portland cement-RHA blend and to assess their applicability for low-volume road construction in Bangladesh. Stabilized samples were prepared at maximum dry density and optimum moisture content determined by AASHTO T99. The samples were cured and tested for durabilty, volume and moisture change characteristics, unconfined compressive strength, and plasticity. Cement-treated alluvial soils satisfy the durability criteria recommended by the Portland Cement Association (PCA) at about 9% cement content. At this cement content, however, they do not attain the specified minimum unconfined compressive strength. Silty soils stabilized with only 2% cement content show considerable gain in unconfined compressive strength over untreated soil. RHA can be blended with cement to stabilize silty soils. A partial replacement of cement by as much as 25% of ash by weight is possible without impairing durability or appreciably decreasing strength compared with samples containing cement only. RHA addition results in an increase in volume on wetting of the soil-cement-RHA mixture and decreases the maximum dry density of the soil. Higher ash content results in an increase in the plasticity of the cement-RHA-stabilized soil.

Soil Cement is Big in Texas Water Projects

Abstract: The State of Texas is a leader in soil cement water-resource applications. Many uses of soil cement for water control had their initial application in Texas. The article describes some of the innovations in the design and construction of soil cement that had their start in Texas. The 108 ft high embankmant of the Toledo Bend Dam was the fisrt major dam project in which soil cement slope protection was used. The solid soil cement design for the long low ring dike at the Barney M. Davis Power Station cooling water reservoir is another example. The design of the 63 ft high Palmetto Bend dam, incorporates both the traditional stair stepped soil cement slope protection for the dam and a 'plating' design for the intake channel. At the South Texas Nuclear Project, the soil cement protection for nearly 20 miles of embankment to form a 700-acre cooling water reservoir and a smaller esential cooling pond represents the largest volume of soil cement used for a water control project worldwide. The design of the Richland-Chambers dam is described, and design trends for soil cement water control projects are discussed.

Testing techniques for evaluating the shear strength of lime/fly ash slurry stabilized soil

Abstract: Lime slurry pressure injections have been successfully used to stabilize and control swelling and expansive soils and low-strength clay soils to depths of up to 40 ft (12 m). When the activity of soils is somewhat lower, or when soils have large void ratios, lime/fly ash (L/FA) slurry mixtures have been injected to fill voids. It has been postulated that this action creates stronger seams, helps to mend possible failure surfaces, and at the same time increases the overall stability of a slope by decreasing water infiltration. The investigation reported herein was undertaken to develop laboratory testing techniques suitable for evaluating the strength improvement realized by introducing L/FA into a soil mass in the form of seams. To accomplish this goal, six specimen configurations were conceived, and a total of 45 direct shear specimens, including 35 containing vertical and/or horizontal seams of L/FA, were tested. In addition to demonstrating the viability of testing techniques developed, the testing program resulted in a small data base on one soil stabilized with an L/FA slurry having a lime-to-fly ash weight ratio of 1:3.75 and a solids-to-water ratio of 7.6 lb to 1 gal (0.9 kg to 1 L).

Stabilization of Collapsible Alluvial Soil Using Dynamic Compaction

Abstract: The effectiveness of dynamic compaction for improving collapsible soils was evaluated under field conditions using full scale load tests performed on 1.5 m square footings. Tests were performed on untreated soil and soil stabilized by dynamic compaction at the natural moisture content and after pre-wetting. Particle velocity attenuation was measured. Soil improvement was evaluated using double oedometer testing on 'undisturbed' samples as well as CPT and PMT testing. Settlements were predicted by lab testing and actual settlement was monitored as a function of moisture penetration. Dynamic compaction decreased settlement from 400 mm to less than 30 mm. Pre-wetting showed promise for more effective compaction.

Soil stabilization using oil shale solid wastes: Laboratory evaluation of engineering properties

Abstract: Oil shale solid wastes were evaluated for possible use as soil stabilizers. A laboratory study was conducted and consisted of the following tests on compacted samples of soil treated with water and spent oil shale: unconfined compressive strength, moisture-density relationships, wet-dry and freeze-thaw durability, and resilient modulus. Significant increases in strength, durability, and resilient modulus were obtained by treating a silty sand with combusted western oil shale. Moderate increases in strength, durability, and resilient modulus were obtained by treating a highly plastic clay with combusted western oil shale. Solid waste from eastern shale can be used for soil stabilization if limestone is added during combustion. Without limestone, eastern oil shale waste exhibits little or no cementation. The testing methods, results, and recommendations for mix design of spent shale-stabilized pavement subgrades are presented. 11 refs., 3 figs., 10 tabs.

COE Design of Cement Stabilized Base Courses for Airfield Pavements

Abstract: The U.S. Army Corps of Engineers (COE) develops design criteria, guide specifications, and other tehcnical guidance information that are used for pavement design and contract specifications preparation. Changes and new concepts introduced in the area of the design of pavements with cement stabilized base courses are discussed in this paper. Four technical manuals (TM) applicable in the design of cement stabilized base courses are considered. They are as follows: TM 5-822-4 - Soil Stabilization for Pavements; TM 5-825-2 - Flexible Pavement Design for Airfields; TM 5-8253 - Rigid Pavements for Airfields; TM 5-818-2 Pavement Design for Seasonal Frost Conditions.

Bureau of reclamation soil-cement slope protection

Abstract: Observations over several years by the Bureau of Recalamation have shown soil cement to be a safe and economical alternative to riprap. The Bureau, however, continues to look for methods to improve long-term performance. Recent changes to soil cement design and construction are being monitored. The history of the evaluation of soil cement slope protection projects is described. Soil cement slope protection has required repair on 3 projects because of damage sustained during major storms or because of normal wear. These include the Merrit Dam in Nebraska, the Cheney Dam in Kansas, and Lubbock Regulating Reservoir in Texas. Recent changes to reclamation specifications are also described.

Soil stabilisation using rice husk ash

Abstract: Rice husk ash (RHA) has been investigated as a pozzolanic material for soil stabilisation. It contains siliceous and aluminous materials, and reacts with lime or cement, thus having the economic potential to replace some of the lime or cement presently used as an additive in the stabilisation of soil. Three types of soil were treated with varying quantities of lime, cement, RHA and combinations of RHA with lime or cement, under laboratory conditions. To determine the effectiveness of RHA as a stabiliser, unconfined compressive strength (UCS), plasticity index and linear shrinkage were measured for the treated soils A using standard Road Traffic Authority of New South Wales (RTA NSW) tests. RHA alone was shown to be unsuitable for modifying soil properties. However, when combined with lime or cement, beneficial results were obtained. The effectiveness of the RHA was expressed in terms of the ratio of the RHA required to either lime or cement saved. RHA is produced by the burning of rice husks (also known as rice hulls), which currently are a little-used by-product of the rice industry, presenting disposal problems worldwide. Information on present and likely future availability of RHA in Australia is included in this paper.

Long-term Durability of Soil Solidified with Hydrophobic Polyisocyanate-type Grout.

Abstract: At a construction work, chemical grouting for soil stabilization is generally used only for temporary purpose. However, hydrophobic polyisocyanate-type ‹aquareactive› grout named TACSS has been often applied for permanent use such as strengthening the ground under the foundation or piles of structure.Since the gel produced by an aqua-reaction is non-hydrated and has three dimensional chemical structures, it is considered that gel product formed in the soil and water can be expected to maintain the stable condition without loosing it's strength characteristics. However, experimental data about the durability of soil solidified with grout was not yet obtained, and so a follow-up test has been carried out to confirm the durability experimentally. Test specimens of soil solidified with grout were burned in the ground impregnated with an industrial chemical waste or dipped in various kinds of water such as sea water and muddy humes etc. for 19-22 years.During those years they were occasionally taken out from the ground or water and a non-destructive follow-up test was proceeded by measuring the velocity of ultrasonic wave.The durability test was completed this time and all of the specimens were submitted to the bending tests and unconfined compressive strength tests. As a result of this experiment, it is proved that the mechanical properties of soil solidified with hydrophobic polyisocyanate-type grout are superior and can maintain the mechanical characteristics without deterioration by leaching, swelling, softening etc. even under the strict circumstances for a long term of about 20 years.

Pavement subbases. final report

Abstract: This report describes the development of a complete pavement system which incorporates an open graded drainage layer to effectively remove infiltrated water. Candidate materials for use as open graded drainage layers were investigated using laboratory studies of flow characteristics and loading studies to measure accumulated deformations. The research team found that the required hydraulic conductivity of an open graded drainage layer must exceed 1,000 fpd for typical interstate design. For extreme conditions, hydraulic conductivity requirements may approach 5,000 fpd. Two standard Illinois DOT aggregate gradations, CA-7 and CA-11, were found to have hydraulic conductivities in excess of 5,000 fpd. Stability tests conducted on the open graded drainage layers indicate that stabilization with PCC cement or asphalt cement would be required if the materials were to be trafficked prior to final paving. Minimum PCC cement contents of 6% by weight of aggregate are required for adequate stabilization. Minimum asphalt cement contents of 2.5% are required. Observations of open graded drainage layer construction projects were made to document the practicality of construction. These observations indicate open graded drainage layers may be successfully placed if construction equipment specially suited to these materials is used.